Add Python snippet example.

users/jrpotter/neovim/config/python/snippets.lua

@@ -1,16 +1,58 @@
-local s = require('luasnip').snippet
+local c = require('luasnip').choice_node
+local d = require('luasnip').dynamic_node
 local i = require('luasnip').insert_node
+local sn = require('luasnip').snippet_node
+local t = require('luasnip').text_node
+
+local s = require('luasnip').snippet
 local fmt = require('luasnip.extras.fmt').fmt
 
-local v = require('utils.snippets').visual_dynamic_node
+local VISUAL = require('utils.luasnip').VISUAL
 
 return {
   s(
     { name = 'for', trig = 'for' },
     fmt([[
 for {} in {}:
-  {}]],
-      { i(1, ''), i(2, ''), v(3) }
+    {}]],
+      {
+        c(1, {
+          i(1, 'i'),
+          i(2, 'k'),
+          i(3, 'v'),
+          sn(4, { i(1, 'k'), t(', '), i(2, 'v') }),
+        }),
+        d(2, function(args, _, old_state)
+          local default = i(nil, 'val')
+          local snip = old_state or default
+
+          if args[1][1] == 'i' then
+            snip = sn(nil, c(1, {
+              { t('range('), i(1, 'n'), t(')') },
+              default,
+            }))
+          elseif args[1][1] == 'k' then
+            snip = sn(nil, c(1, {
+              { i(1, 'dict'), t('.keys()') },
+              default,
+            }))
+          elseif args[1][1] == 'v' then
+            snip = sn(nil, c(1, {
+              { i(1, 'dict'), t('.values()') },
+              default,
+            }))
+          elseif args[1][1] == 'k, v' then
+            snip = sn(nil, c(1, {
+              { i(1, 'dict'), t('.items()') },
+              default,
+            }))
+          end
+
+          snip.old_state = snip
+          return snip
+        end, { 1 }),
+        VISUAL,
+      }
     )
   ),
 }

users/jrpotter/neovim/config/utils/cmp.lua

@@ -2,7 +2,7 @@ local M = {}
 
 local cmp = require('cmp')
 local cmp_buffer = require('cmp_buffer')
-local luasnip = require("luasnip")
+local luasnip = require('luasnip')
 
 function M.setup()
   cmp.setup {
@@ -12,9 +12,8 @@ function M.setup()
       end,
     },
     sources = {
-      {
-        name = 'nvim_lsp',
-      },
+      { name = 'luasnip' },
+      { name = 'nvim_lsp' },
       {
         name = 'buffer',
         option = {
@@ -31,29 +30,24 @@ function M.setup()
     },
     sorting = {
       comparators = {
-        function (...)
-          -- This also sorts completion results coming from other sources (e.g.
-          -- LSPs).
+        function(...)
+          -- This also sorts completion results coming from other sources.
           return cmp_buffer:compare_locality(...)
         end,
       },
     },
     mapping = {
-      ['<c-n>'] = cmp.mapping(function(fallback)
-        if cmp.visible() then cmp.select_next_item() else fallback() end
-      end, { 'i', 's' }),
-
-      ['<c-p>'] = cmp.mapping(function(fallback)
-        if cmp.visible() then cmp.select_prev_item() else fallback() end
+      ['<tab>'] = cmp.mapping(function(fallback)
+        if cmp.get_active_entry() then cmp.confirm() else fallback() end
       end, { 'i', 's' }),
 
       ['<c-l>'] = cmp.mapping(function(fallback)
         if cmp.visible() then cmp.abort() else fallback() end
       end, { 'i', 's' }),
 
-      ['<tab>'] = cmp.mapping(function(fallback)
-        if cmp.get_active_entry() then
-          cmp.confirm()
+      ['<c-n>'] = cmp.mapping(function(fallback)
+        if cmp.visible() then
+          cmp.select_next_item()
         elseif luasnip.expand_or_locally_jumpable() then
           luasnip.expand_or_jump()
         else
@@ -61,8 +55,10 @@ function M.setup()
         end
       end, { 'i', 's' }),
 
-      ['<s-tab>'] = cmp.mapping(function(fallback)
-        if luasnip.jumpable(-1) then
+      ['<c-p>'] = cmp.mapping(function(fallback)
+        if cmp.visible() then
+          cmp.select_prev_item()
+        elseif luasnip.locally_jumpable(-1) then
           luasnip.jump(-1)
         else
           fallback()

users/jrpotter/neovim/config/utils/luasnip.lua

@@ -0,0 +1,64 @@
+local M = {}
+
+local luasnip = require('luasnip')
+local types = require('luasnip.util.types')
+local f = require('luasnip').function_node
+
+M.VISUAL = f(function(_, snip)
+  local res, env = {}, snip.env
+  for _, ele in ipairs(env.LS_SELECT_RAW) do
+    table.insert(res, ele)
+  end
+  return res
+end, {})
+
+function M.setup()
+  luasnip.config.setup {
+    region_check_events = 'InsertEnter',
+    delete_check_events = 'InsertLeave',
+    store_selection_keys = '<tab>',
+    ext_opts = {
+      [types.snippet] = {
+        active = {
+          virt_text = { { '●', 'DiagnosticWarn' } },
+        },
+      },
+      [types.choiceNode] = {
+        active = {
+          virt_text = { { '⧨', 'DiagnosticHint' } },
+          -- Include in case one of our choice options is an empty string.
+          hl_group = 'DiagnosticOk',
+        },
+      },
+    },
+  }
+
+  vim.keymap.set(
+    { 'i', 's' },
+    '<c-e>',
+    function()
+      if luasnip.choice_active() then
+        luasnip.change_choice(1)
+      end
+    end,
+    { silent = true }
+  )
+  vim.keymap.set(
+    { 'i', 's' },
+    '<c-y>',
+    function()
+      if luasnip.choice_active() then
+        luasnip.change_choice(-1)
+      end
+    end,
+    { silent = true }
+  )
+  -- Allow aborting the active snippet at any point in time.
+  vim.keymap.set(
+    { 'n', 'i', 's' },
+    '<c-l>',
+    '<cmd>LuaSnipUnlinkCurrent<cr>'
+  )
+end
+
+return M

users/jrpotter/neovim/config/utils/snippets.lua

@@ -1,28 +0,0 @@
-local M = {}
-
-local luasnip = require('luasnip')
-local d = luasnip.dynamic_node
-local i = luasnip.insert_node
-local sn = luasnip.snippet_node
-
--- Creates an insertion node with a default value of whatever was stored in the
--- visual selection prior to entering insert mode (refer to the configuration
--- field `store_selection_keys`).
-function M.visual_dynamic_node(index, default)
-  return d(index, function(_, parent)
-    local res, env = {}, parent.snippet.env
-    if type(env.LS_SELECT_RAW) ~= 'table' then
-      return sn(nil, { i(1, default or '') }, '')
-    end
-    for k, v in ipairs(env.LS_SELECT_RAW) do
-      local indent = env.CUSTOM_POS[2] - 1
-      table.insert(res, (k == 1 and v) or string.rep(' ', indent) .. v)
-    end
-    if table.concat(res):match('^%s*$') then
-      return sn(nil, { i(1, default or '') }, '')
-    end
-    return sn(nil, { i(1, res) }, '')
-  end, {})
-end
-
-return M

users/jrpotter/neovim/default.nix

@@ -30,6 +30,7 @@ let
   luasnip = {
     plugin = pkgs.vimPlugins.luasnip;
     config = ''
+      require('utils.luasnip').setup()
       ${config.programs.neovim.nvim-snippets}
     '';
   };